Rapid genome-wide introgression reveals fitness advantage of immigrant genotypes.

ABSTRACT: Evolutionary biology has long recognized the tendency for populations to be locally adapted to their ancestral habitat, resulting in higher resident fitness. However, immigrants can also introduce beneficial alleles. The resulting adaptive introgression is usually inferred retrospectively, rather than as a contemporary process. Here, we document exceptionally rapid ongoing adaptive introgression in a lake population of threespine stickleback (Gasterosteus aculeatus). In the first generations after a discrete immigration event, all chromosomes exhibited large increases in immigrant ancestry due to linkage disequilibrium. After a decade, the extent of introgression varied across the genome. The fastest-evolving genes included Spi1b, which enables an increased fibrosis defense a

SUBMITTER: Flanagan BA 

PROVIDER: S-EPMC12407968 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature